I posted a story about the Navajo Dam spilling for the facebook page of the San Juan County Historical Society (New Mexico). I noted that it had only spilled once, in 1973. The comments were interesting. Many people fondly recalled seeing it spill in the 1980s and 1990s. I was the park superintendent of Navajo Lake State Park (the New Mexico side) for many years and knew I was correct about the 1973 spill and the Bureau of Reclamation historical records support my recollection. Here is a link to that story.